1. Field of the Invention
The present invention relates to techniques for generating power. More particularly, the invention relates to techniques for generating power using a thermodynamic system with a working fluid passing therethrough.
2. Background of the Related Art
Various devices have been developed to generate power to perform necessary work. For example, engines have been designed to propel vehicles, operate factory equipment and generate electricity. Some such engines take an input, such as coal, gas or other fuel, and convert such fuel into an output, typically in the form of kinetic energy, to perform the work.
Over time, power generators have been refined in an effort to improve performance and/or efficiency. Advancements in performance have enabled the development of more sophisticated devices capable of operating high power equipment, such as nuclear reactors, rockets and/or jet engines. See, for example, the technology path of turbomachinery as described in C. DellaCorte, Gas Bearing Development for SCO2 Applications, Presentation at NASA Glenn Research Center, Cleveland, Ohio, 2006.
One enhancement of power generation is the development of the Brayton Cycle (sometimes referred to as the Joule Cycle). With the Brayton Cycle, working fluid is compressed by a compressor and passed through a turbine to generate power for performing desired work. The Brayton Cycle typically involves a closed loop system that returns the fluid from the turbine back to the compressor for reuse. Examples of Brayton Cycles are described in the following articles: Wright S. A., Preliminary Results of Dynamic System Model for a Closed-Loop Brayton Cycle Coupled to a Nuclear Reactor,” Proceedings 1st International Energy Conversion Engineering Conference, Portsmouth, Va., (Aug. 17-21, 2003); Steven A. Wright, Measured and Modeled Turbomachinery Operating Characteristics in a Closed Brayton Cycle Test Loop, ANS Winter Meeting, Albuquerque, N. Mex., (Nov. 12-16, 2006), p. 855-57; S. A. Wright, Robert Fuller, et. al., Operational Results of a Closed Brayton Cycle Test-Loop, Proceedings of Space Technology and Applications International Forum (STAIF-2005) Albuquerque, N. Mex. (February, 2005), pg 699; S. A. Wright, and R. J. Lipinski Operational Curves for HTGR's Coupled to Closed Brayton Cycle Power Conversion Systems, Proceedings of International Congress on Advances in Nuclear Power Plants, Reno, Nev. (Jun. 4-8 2006); S. A. Wright and R. J. Lipinski, Self-Driven Decay Heat Removal in a GCR Closed Brayton Cycle Power System, Proceedings of International Congress on Advances in Nuclear Power Plants, Reno Nev., (Jun. 4-8, 2006); S. A. Wright and P. S. Pickard, Impact of Closed Brayton Cycle Test Results on Gas Cooled Reactor Operation and Safety, Proceedings of International Congress on Advances in Nuclear Power Plants, Nice, France (May 13-18, 2007); Steven A. Wright, Non-Nuclear Validation Test Results of a Closed Brayton Cycle Test-Loop, Proceedings of Space Technology and Applications International Forum (STAIF-2007), Albuquerque, N. Mex., (Feb. 11-15, 2007); AIP Conference Proceedings, Volume 880, (2007) pp. 157-166; and Steven A. Wright, Supercritical Brayton Cycle Nuclear Power System Concepts, in Proceedings of Space Technology and Applications International Forum (STAIF-2007), Albuquerque, N. Mex., (Feb. 11-15, 2007); AIP Conference Proceedings, Volume 880, (2007) pp. 597-604.
Various factors may affect the operation of power generation systems. For example, inefficiencies, such as windage, can affect performance as described in J. E. Vrancik, Prediction of Windage Power Loss in Alternators, NASA Technical Note, NASA TN-D-4849 (October 1968), the entire contents of which is hereby incorporated by reference. Additionally, certain fluids used in a power generation system can affect operation as described, for example, in V. Dostal, M. J. Driscoll, P. Hejzlar, A Supercritical Carbon Dioxide Cycle for Next Generation Nuclear Reactors, MIT-ANP-TR-100 (Mar. 10, 2004), the entire contents of which is hereby incorporated by reference.
Despite the previous advancements in power generation, there remains a need to provide techniques for dealing with the various operational factors and/or optimizing the operation of power generation systems. It is desirable that power generation systems utilize closed loop Brayton Cycles that are capable of operating at even supercritical conditions (e.g., high-pressure and high density). In such cases, it is desirable to provide features to isolate components of the system from harsh conditions, provide hermetic conditions and/or to handle the loads applied to the system. Preferably, such systems are capable of cooling components, reducing losses and/or failures, operating at even extreme conditions (e.g., high thrust loads, pressures and/or densities) and/or otherwise enhancing operation. The present invention is provided to address these and other needs.